package com.hmdp.service.impl;

import cn.hutool.core.util.BooleanUtil;
import cn.hutool.core.util.StrUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import com.hmdp.dto.Result;
import com.hmdp.entity.Shop;
import com.hmdp.mapper.ShopMapper;
import com.hmdp.service.IShopService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.CacheClient;
import com.hmdp.utils.RedisConstants;
import com.hmdp.utils.RedisData;
import com.hmdp.utils.SystemConstants;
/*import org.springframework.data.domain.Page;*/
import org.springframework.data.geo.Distance;
import org.springframework.data.geo.GeoResult;
import org.springframework.data.geo.GeoResults;
import org.springframework.data.redis.connection.RedisGeoCommands;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.domain.geo.GeoReference;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.Resource;

import java.time.LocalDateTime;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;

import static com.hmdp.utils.RedisConstants.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class ShopServiceImpl extends ServiceImpl<ShopMapper, Shop> implements IShopService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private CacheClient cacheClient;

    @Resource
    public IShopService shopService;

    @Override
    public Result queryById(Long id) {
        //TODO 缓存穿透
        //Shop shop = queryWithPassThrough(id);
        //Shop shop = cacheClient
        //       .queryWithPassThrough(CACHE_SHOP_KEY, id, Shop.class, this::getById, CACHE_SHOP_TTL, TimeUnit.MINUTES);

        //TODO 互斥锁解决缓存击穿
        //Shop shop = queryWithMutes(id);

        //TODO 逻辑过期解决缓存击穿
        //Shop shop = queryWithLogicalExpire(id);
        Shop shop = cacheClient
                .queryWithLogicalExpire(CACHE_SHOP_KEY, id, Shop.class, this::getById, 20L, TimeUnit.SECONDS);

        if (shop == null){
            return Result.fail("店铺不存在！！");
        }
        //7.返回
        return Result.ok(shop);
    }


//    //TODO 创建线程池
   private static final ExecutorService CACHE_REBUILD_EXECUTOR = Executors.newFixedThreadPool(10);
/*
    //TODO 逻辑过期解决缓存击穿问题
    public Shop queryWithLogicalExpire(Long id){
        //提前创建一个key值，将"cache:shop:"封装为一个常量，放在RedisConstants中
        String key =  CACHE_SHOP_KEY + id;
        //1.从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isBlank(shopJson)) {
            //3.不存在，直接返回空
            return null;
        }
        //TODO 4.命中，需要先把json反序列化为对象
        RedisData redisData = JSONUtil.toBean(shopJson, RedisData.class);
        JSONObject data =(JSONObject) redisData.getData();
        Shop shop = JSONUtil.toBean(data, Shop.class);
        LocalDateTime expireTime = redisData.getExpireTime();

        //TODO 5.判断是否过期
        if (expireTime.isAfter(LocalDateTime.now())) {
            //TODO 5.1 未过期，直接返回店铺信息
            return shop;
        }
        //TODO 5.2 已过期，需要缓存重建
        //TODO 6.缓存重建
        //TODO 6.1 获取互斥锁
        String lockKey = LOCK_SHOP_KEY + id;
        boolean isLock = tryLock(lockKey);
        //TODO 6.2 判断是否获取锁成功
        if (isLock){
            //TODO 6.3 成功，开启独立线程，实现缓存重建
            CACHE_REBUILD_EXECUTOR.submit(()->{
                try {
                    //重建缓存
                    this.saveShop2Redis(id,20L);
                } catch (Exception e) {
                    throw new RuntimeException(e);
                }finally {
                    //释放锁
                    unLock(lockKey);
                }
            });
        }
        //TODO 6.4 返回过期的商铺信息
        return shop;
    }*/


    //TODO 互斥锁解决缓存击穿
/*    public Shop queryWithMutes(Long id){
        //提前创建一个key值，将"cache:shop:"封装为一个常量，放在RedisConstants中
        String key =  CACHE_SHOP_KEY + id;

        //1.从redis查询商铺缓存
        String shopJson = stringRedisTemplate.opsForValue().get(key);
        //2.判断是否存在
        if (StrUtil.isNotBlank(shopJson)) {
            //3.存在，直接返回
            //将shopJson转换为shop实体类型
            return JSONUtil.toBean(shopJson, Shop.class);
        }
        //缓存穿透，判断命中的是否是空值
        if (shopJson != null){    //不等于null，也就是空字符串
            //返回错误信息
            return null;
        }

        //TODO 4.实现缓存重建
        //TODO 4.1 获取互斥锁
        String lockKey = "lock:shop:" + id;
        Shop shop = null;
        try {
            boolean isLock = tryLock(lockKey);
            //TODO 4.2 判断是否获取成功
            if (!isLock){
                //TODO 4.3 失败，则休眠
                Thread.sleep(50);
                 return queryWithMutes(id);
            }

            //4.4 成功，根据id查询数据库
            shop = getById(id);
            //TODO 模拟重建的延时
            Thread.sleep(200);
            //5.不存在，返回错误
            if (shop == null) {
                //将空值写入redis
                stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
                //返回错误信息
                return null;
            }
            //6.存在，写入redis   将shop转为一个Jsonstring类型存入redis
            stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }finally {
            //TODO 7. 释放互斥锁
            unLock(lockKey);
        }

        //8.返回
        return shop;
    }*/


//    //TODO 缓存穿透
//    public Shop queryWithPassThrough(Long id){
//        //提前创建一个key值，将"cache:shop:"封装为一个常量，放在RedisConstants中
//        String key =  CACHE_SHOP_KEY + id;
//        //1.从redis查询商铺缓存
//        String shopJson = stringRedisTemplate.opsForValue().get(key);
//        //2.判断是否存在
//        if (StrUtil.isNotBlank(shopJson)) {
//            //3.存在，直接返回
//            //将shopJson转换为shop实体类型
//            return JSONUtil.toBean(shopJson, Shop.class);
//        }
//        //TODO 缓存穿透，判断命中的是否是空值
//        if (shopJson != null){    //不等于null，也就是空字符串
//            //返回错误信息
//            return null;
//        }
//        //4.不存在，根据id查询数据库
//        Shop shop = getById(id);
//        //5.不存在，返回错误
//        if (shop == null) {
//            //TODO 将空值写入redis
//            stringRedisTemplate.opsForValue().set(key,"",CACHE_NULL_TTL, TimeUnit.MINUTES);
//            //返回错误信息
//            return null;
//        }
//        //6.存在，写入redis   将shop转为一个Jsonstring类型存入redis
//        stringRedisTemplate.opsForValue().set(key,JSONUtil.toJsonStr(shop),CACHE_SHOP_TTL, TimeUnit.MINUTES);
//        //7.返回
//        return shop;
//    }


/*
    //TODO 获取锁
    private boolean tryLock(String key){
        Boolean flag = stringRedisTemplate.opsForValue().setIfAbsent(key, "1", 10, TimeUnit.SECONDS);
        return BooleanUtil.isTrue(flag);
    }
    //TODO 释放锁
    private void unLock(String key){
        stringRedisTemplate.delete(key);
    }
*/


    //TODO 将shop添加到redis中
    /*public void saveShop2Redis(Long id,Long expireSeconds) throws InterruptedException{
        //1.查询店铺数据
        Shop shop = getById(id);
        Thread.sleep(200);
        //2.封装逻辑过期时间
        RedisData redisData = new RedisData();
        redisData.setData(shop);
        redisData.setExpireTime(LocalDateTime.now().plusSeconds(expireSeconds));
        //3.写入Redis
        stringRedisTemplate.opsForValue().set(CACHE_SHOP_KEY + id, JSONUtil.toJsonStr(redisData));
    }*/

    @Override
    @Transactional    //通过事务实现回滚，控制他们的原子性
    public Result update(Shop shop) {
        Long id = shop.getId();
        if (id == null){
            return Result.fail("店铺id不能为空！");
        }
        //1.更新数据库
        updateById(shop);
        //2.删除缓存
        stringRedisTemplate.delete(CACHE_SHOP_KEY + shop.getId());
        return Result.ok();
    }

    /**
     * 附近商户功能实现
     * @param typeId
     * @param current
     * @param x
     * @param y
     * @return
     */
    @Override
    public Result queryShopByType(Integer typeId, Integer current, Double x, Double y) {
        //1. 判断是否需要根据坐标查询
        if(x==null || y==null){
            //不需要查询坐标，按数据库查
            Page<Shop> page = query()
                    .eq("type_id",typeId)
                    .page(new Page<>(current, SystemConstants.DEFAULT_PAGE_SIZE));
            return Result.ok(page.getRecords());
        }
        //2. 计算分页参数
        int fron = (current - 1) * SystemConstants.DEFAULT_PAGE_SIZE;
        int end = current * SystemConstants.DEFAULT_PAGE_SIZE;
        //3. 查询redis，按照距离排序、分页  结果：shopId，distance
        String key = SHOP_GEO_KEY + typeId;
        GeoResults<RedisGeoCommands.GeoLocation<String>> results = stringRedisTemplate.opsForGeo()     //GEOSEARCH key BYLONLAT x y BYRADIUS 10 WITHSTANCE
                .search(key,
                        GeoReference.fromCoordinate(x, y),
                        new Distance(5000),
                        RedisGeoCommands.GeoSearchCommandArgs.newGeoSearchArgs().includeCoordinates().limit(end)
                );
        //4. 解析出id
        if (results == null){
            return Result.ok(Collections.emptyList());
        }
        List<GeoResult<RedisGeoCommands.GeoLocation<String>>> content = results.getContent();
        if(list().size() <= fron){
            //没有下一页了，结束
            return Result.ok(Collections.emptyList());
        }
        //4.1 截取从from到end的部分
        List<Long> ids = new ArrayList<>(list().size());
        Map<String,Double> distanceMap = new HashMap<>(list().size());
        list().stream().skip(fron).forEach(result ->{
            //4.2 获取店铺id
            String shopIdStr = result.getName();
            ids.add(Long.valueOf(shopIdStr));
            //4.3 获取距离
            Double distance = result.getDistance();
            distanceMap.put(shopIdStr, distance);
        });
        //5. 根据id查询shop
        String idStr = StrUtil.join(",", ids);
        List<Shop> shops = query().in("id", ids).last("ORDER BY FIELD (id," + idStr + ")").list();
        //6.返回
        return null;
    }
}
